This specification relates to digital information retrieval, and particularly to search processing.
The Internet enables access to a wide variety of resources, such as video or audio files, web pages for particular subjects, book articles, or news articles. A search engine can identify resources in response to a user query that includes one or more search terms or phrases. The search engine ranks the resources based on their relevance to the query and importance and provides search results that link to the identified resources. The search results are typically ordered according to the rank, and are provided to user devices according to the rank.
Search engines score resources based on a variety of factors. Examples of such factors include an information retrieval score and an authority score. The information retrieval score is a measure of relevance of a query to resource content, and the authority score is a measure of importance of a resource relative to other resources.
Additional factors can also be used to score resources, or to adjust resource scores after scoring by the search engine. One example is user feedback. Resources that tend to satisfy users' informational needs are typically selected more frequently than resources that do not tend to satisfy users' informational needs for certain queries. Search and selection data are stored by the search engine, and thus the search engine can determine, for certain queries, which resources tend to better satisfy users' informational needs. Based on this information, the search scores can be adjusted so that better performing resources receive a scoring “boost.”
Some resources, however, do not have a sufficient corpus of search and selection data from which an inference of performance can be drawn. For example, a newly published resource initially has no associated search and selection data.